Highway grating



Jan. 4 H. c. DREIBUSS ET AL HIGHWAY GRATING Filed June 17, 1940 THE/l?147- To mm K5.

Patented Jan. 13, 1942 arse STATES HIGHWAY GRATING Harry C. Dreibuss andFred H. Spenner, St. Louis, Mo., assignorsto Scullin Steel Co, St.Louis, Mo a corporation of Missouri Application June 17, 1940, SerialNo. 340,960

4 Claims.

Our invention relates to gratings, particularly to highway gratings ofthe type that span drainage or vault openings in the roadway and aresubmitted to the full brunt of trafiic. The principal objects of thepresent invention are to devise a highway grating that will be able towithstand the stresses imposed by heavy vehicular traffic, that can bemade of cast steel, that will have a maximum strength and a maximum areaof inlet openings for the amount of metal embodied therein and whoseopenings will be selfcleaning.

The invention consists principally in a cast steel grating withcontinuous sides and ends, and

with cross beams extending from side to side, all

of said beams having their end portions extended below the side membersand terminating in the same horizontal plane; it also consists in such agrating wherein the cross members consist of one series, whose bottomstraight from the downward enlargement at one end thereof to thedownward enlargement at the other end thereof, and a second seriesalternating with those of the first series and whose depth near theirend enlargements is substantially equal to the depth of the crossmembers of the first series and which increase in depth to a maximumdepth midway of their length; it also consists in such a grating whereinthere are two members extending longitudinally from end to end withtheir top substantially flush with the tops of the cross members, thesides and cross members defining openings whose side walls divergedownwardly to make the device selfcleaning; and it also consists in thecombina-v tions hereinafter described and claimed.

In the accompanying drawing, which forms part of the specification andwherein like symbols and like reference numerals refer to lik partswherever they occur:

Fig. 1 is a plan view of a highway grating embodying our invention,

Fig. 2 is an end View of said grating,

Fig. 3 is a cross-sectional View on the line 3-3 in Fig. 1,

Fig. 4 is a longitudinal sectional view on the line 44 in Fig. 1,

Fig. 5 is a fragmentary side elevational view of said grating; and

Fig. 6 is an enlarged fragmentary vertical cross-section, showing ourhighway grating seated on a bearin plate in a drainage inlet opening.

Our highway grating is cast in a single piece of steel. It is ofrectangular outline with conedge is substantially? tinuous straight sidemembers I and two series of cross connecting members 2 and 3respectively, extending from side member to side member. All of thecross members 2 and 3 are of substantially even height with the sidemembers I. The cross members. 2 of one series are, throughout thegreater portion of their length, straight and of substantially evendepth with the side members, but their end portions are extendeddownwardly, as at t, below the plane of the side members I. The crossmembers .3 of the second series are arranged alternately with the crossmembers 2 of the first series and have downwardly extending end portions5 of the same depth and shape as the end portions 4 of the cross membersof the first series. Near the end portions 5 of the cross members 3 ofthe second series, the depth thereof is substantially equal to the depthof the intermediate portion of the cross members 2 of the first seriesand from these points the depth of the cross-members of the secondseries increases gradually to the middle portions 6 thereof where thedepth is somewhat greater than at the downwardly extending end portions5 thereof.

Extending lengthwise of the grating from end to end thereof are twolongitudinal members I of substantially even depth with the side.members I and the intermediate portions of the shallow cross members 2.There are two of these longitudinal members 1 spaced evenly from eachother and from the side members I of the grate. Thus a row of elongatedopenings 8 of even length are formed between the cross members 2 and 3and the longitudinal two members 1 and additional rows of openings 9 ofthe same size are formed along each side of the middle row between saidcross members, said longitudinal members and the side members I of thegrate. The side members I, cross members 2 and 3 and longitudinalmembers 'I taper in width from top v to bottom, whereby the openings 8and 9 have downwardly diverging side and end walls which make saidopenings self-cleaning,

The width of each opening is. determined with reference to requirementsof trafiic and the total area of the openings is determined by referenceto rainfall or other drainage consideration or ventilation and thelength of the grating will vary with the required total area openings.On the other hand, the strength of the grating, the selfcleaningfunctionand its economical use of the materials are dependent upon thestructural design of the grating and particularly upon functionalcoordination of the several parts thereof.

Thus all the cross members 2 and 3 function as beams to sustain verticalload. By making the shallow beams of less depth than the deep beams, thevertical depth of the openings between the deep and shallow beams isshortened with consequent decrease of the probability of trapping litterthat might be unable to go through an opening of the same width withgreater depth; and by extending the end portions of both the shallow anddeep beams downwardly below the bottoms of the side members I, theopenings 9 between adjacent beams open, as at 9a, through the sides ofthe grating below said side members.

The longitudinal members I serve to stabilize the cross members 2 and 3and prevent them from buckling under beam action. The end portions 4 and5 of the cross or transverse members 2 and 3, respectively, being theportions of increased depth, are intended to rest upon a bearing plateI!) provided therefor in the Wall ll of the inlet opening of the drainor vault system. Thus, there is a concentration of stresses, principallyshearing stress, just inwardly of the end bearing portions 4 and 5 ofthe cross members 2 and 3 and such stresses are relieved by increasingthe depth of all said members or beams from points somewhat inwardly ofsaid end portions to the inner ends thereof; that is, by the addition ofthe fillets l2 and I3 that round or fill out the angles between deep endportions 4 and 5, respectively, of said cross members and the adjacentshallow portions thereof. These fillets function as gussets and are welladapted to stiffen and strengthen the cross or transverse members 2 and3.

As stated above, the width of the openings in the grating is determinedby the requirements of trafiic; but the length of the openings is withinthe control of the designer, the greater the length consistent withstrength and economy, the more eificient it is for self-cleaning. It isfor this reason that two longitudinal members I are sufficient toprevent buckling of the cross members 2 and 3 under all reasonabletrafiic loads. It is noted that all parts of our grating cooperatedirectly with one another, the cross members 2 and 3 functioning ascomposite beams are spaced closely together at the top, for a shallowdepth, below which the deeper beams 3 extend but with a wider spacing,while the gusset action of all of the beams near their supports developsgreater strength than would otherwise be obtainable, while thelongitudinal members prevent buckling of the beams and enable them todevelop their efiicient beam strength.

While it is preferable to make the hereinbefore described grating in theform of a one-piece casting, it may be desirable in some instances, tomake the grating of separate sections connected together in any desiredmanner.

What we claim is:

1. A highway drainage grating comprising side members connected by twoseries of spaced cross members having their tops substantially flushwith the tops of said side members and their end portions extendeddownwardly below the bottoms of said side members, the cross members ofone series alternating with those of the other series, the depth of thecross members of one series being substantially uniform between thedownwardly extended end portions thereof, the cross members of the otherseries increasing in depth from their downwardly extended end portionsto points midway of their length.

2. A highway drainage grating comprising side members connected by twoseries of spaced cross members having their tops substantiallyfiushwiththe tops of said side members and their end portions extended downwardlybelow the bottoms of said side members and terminating in substantiallythe same horizontal plane, the depth of said cross members of one seriesbetween their downwardly extended end portions being substantially thesame as the depth of said side members, the cross members of the otherseries increasing in depth from their downwardly extended end portionsto a depth at their middle portions greater than the depth of saiddownwardly extended end portions.

3. A highway drainage grating comprising side members connected by twoseries of spaced cross members having their tops substantially flushwith the tops of said side members, the cross members of both serieshaving their end portions extended downwardly below the bottoms of saidside members and terminating in the same horizontal plane, the crossmembers of one series having a depth intermediate their downwardlyextended end portions substantially equal to the depth of said sidemembers, the cross members of the other series alternating with those ofthe first series and having a depth which, adjacent to their downwardlyextended end portions, is substantially equal to the depth of said sidemembers and which increases to a maximum depth midway of their length.

4. A highway drainage grating comprising side members connected by twoseries of spaced cross members of even height with said side members,the cross members of both series having their end portions extendeddownwardly, and terminating below the bottoms of said side members inthe same horizontal plane, the cross members of one series alternatingwith those of the other series the depth of the cross members of oneseries gradually increasing from their downwardly extended end portionsto their middle portions and the depth of the cross members of the otherseries between the downwardly extended end portions thereofcorresponding substantially to the depth of said side members, andspaced longitudinal members extending from end to end of said gratingbetween said side members and of substantially even height and depththerewith, said side members, cross members and longitudinal memberstapering in width from the top to bottom.

HARRY C. DREIBUSS. FRED H. SPENNER.

